System Outline
The ABS is a brake system designed to improve the operability, and secure the stability of the vehicle by preventing the brakes from locking up by controlling the wheel cylinder pressures of all four wheels if the brakes are applied suddenly.
- Input Signals
- Speed sensor signal
The speed of the wheels is detected and sent to TERMINALS FL+, FR+, RL+ and RR+ of the skid control ECU and actuator.
- Stop light SW signal
A signal is sent to TERMINAL STP of the skid control ECU with actuator when the brake pedal is depressed.
- Speed sensor signal
- System Operation
When the wheels have locked-up, the solenoid inside the actuator is activated by a signal from the skid control ECU with actuator, and brake fluid from the wheel cylinders will be released to the reservoir and reduce the hydraulic pressure.
While the ABS is in operation, as the skid control ECU with actuator continuously outputs an operation signal to the pump inside the actuator, and the excess brake fluid stored inside the reservoir will be sucked out by the pump and returned to the master cylinder.
When the hydraulic pressure of the wheel cylinder has decreased or increased to the necessary hydraulic pressure, the solenoid inside the actuator is activated by a control signal from the skid control ECU with actuator, and as a result the hydraulic lines to the wheel cylinder will be closed on both the master cylinder and reservoir sides, and the hydraulic pressure of the wheel cylinder will be maintained at that pressure.
If it becomes necessary to increase the hydraulic pressure in the wheel cylinders, control signals from the skid control ECU with actuator activate the solenoid inside the actuator, to resume the normal operating condition. Thus brake fluid from the master cylinder will be sent to the wheel cylinders and will increase the hydraulic pressure in each wheel cylinder. At this time, if any brake fluid is left in the reservoir, it will be sucked up by the pump inside the actuator and sent to the wheel cylinders.